[nautilus] Add size_request to IconContainer to work around unncecessary relayouting

[Alexander Larsson <alexl src gnome org>]

commit fa6e44717818d7f9239558f81b90c32dceddf58a
Author: Alexander Larsson <alexl redhat com>
Date:   Wed May 4 11:00:45 2011 +0200

    Add size_request to IconContainer to work around unncecessary relayouting
    
    The GtkScrolledWindow uses the widget prefered size as a guess as to
    whether scrollbars are needed or not in the automatic scrollbars case.
    If we don't report anything for them we typically get it wrong and cause
    two size allocate calls on the child each time, with different sizes.
    This (the two sizes speicifically) will cause unnecessary relayouts of
    the window.
    
    So, we just report the current size of the layed out icons as the prefered
    size. This is somewhat wrong as its depending on previous size_allocation
    calls rather than the "ideal" size of the widget, but since the ideal size
    is ignored anyway and just used for this it works well.

 libnautilus-private/nautilus-icon-container.c |   64 +++++++++++++++++++++++++
 1 files changed, 64 insertions(+), 0 deletions(-)
---
diff --git a/libnautilus-private/nautilus-icon-container.c b/libnautilus-private/nautilus-icon-container.c
index 0f6633a..d595f94 100644
--- a/libnautilus-private/nautilus-icon-container.c
+++ b/libnautilus-private/nautilus-icon-container.c
@@ -4101,6 +4101,67 @@ size_allocate (GtkWidget *widget,
 	}
 }
 
+static GtkSizeRequestMode
+get_request_mode (GtkWidget *widget)
+{
+  /* Don't trade size at all, since we get whatever we get anyway. */
+  return GTK_SIZE_REQUEST_CONSTANT_SIZE;
+}
+
+/* We need to implement these since the GtkScrolledWindow uses them
+   to guess whether to show scrollbars or not, and if we don't report
+   anything it'll tend to get it wrong causing double calls
+   to size_allocate (at different sizes) during its size allocation. */
+static void
+get_prefered_width (GtkWidget *widget,
+		    gint      *minimum_size,
+		    gint      *natural_size)
+{
+	EelCanvasGroup *root;
+	double x1, x2;
+	int cx1, cx2;
+	int width;
+
+	root = eel_canvas_root (EEL_CANVAS (widget));
+	eel_canvas_item_get_bounds (EEL_CANVAS_ITEM (root),
+				    &x1, NULL, &x2, NULL);
+	eel_canvas_w2c (EEL_CANVAS (widget), x1, 0, &cx1, NULL);
+	eel_canvas_w2c (EEL_CANVAS (widget), x2, 0, &cx2, NULL);
+
+	width = cx2 - cx1;
+	if (natural_size) {
+		*natural_size = width;
+	}
+	if (minimum_size) {
+		*minimum_size = width;
+	}
+}
+
+static void
+get_prefered_height (GtkWidget *widget,
+		     gint      *minimum_size,
+		     gint      *natural_size)
+{
+	EelCanvasGroup *root;
+	double y1, y2;
+	int cy1, cy2;
+	int height;
+
+	root = eel_canvas_root (EEL_CANVAS (widget));
+	eel_canvas_item_get_bounds (EEL_CANVAS_ITEM (root),
+				    NULL, &y1, NULL, &y2);
+	eel_canvas_w2c (EEL_CANVAS (widget), 0, y1, NULL, &cy1);
+	eel_canvas_w2c (EEL_CANVAS (widget), 0, y2, NULL, &cy2);
+
+	height = cy2 - cy1;
+	if (natural_size) {
+		*natural_size = height;
+	}
+	if (minimum_size) {
+		*minimum_size = height;
+	}
+}
+
 static void
 setup_background (NautilusIconContainer *container)
 {
@@ -5992,6 +6053,9 @@ nautilus_icon_container_class_init (NautilusIconContainerClass *class)
 	widget_class = GTK_WIDGET_CLASS (class);
 	widget_class->destroy = destroy;
 	widget_class->size_allocate = size_allocate;
+	widget_class->get_request_mode = get_request_mode;
+	widget_class->get_preferred_width = get_prefered_width;
+	widget_class->get_preferred_height = get_prefered_height;
 	widget_class->realize = realize;
 	widget_class->unrealize = unrealize;
 	widget_class->button_press_event = button_press_event;